Method of and apparatus for butt-welding pipes



2 Sheets-Sheet 1.

(No Model.)

0. L. OOFFIN. METHOD OF AND APPARATUS FORBUTT WELDING PIPES. No. 537,276.

Patented Apr. 9, 1895.

[WY/EN 012 WIIWESSES (No Model.) 2 Sheets-Sheet 2.

U. L. GOFPIN. METHOD OF AND APPARATUS FOR BUTT'WELDING PIPES. No. 537,276. Patented Apr. 9,1895.

WITNESSES ZNVENTOi? Mel/.14. Z v

CHARLES L. COFFIN, OF DETROIT, MICHIGAN.

METHOD OF AND APPARATUS FOR BUTT-WELDING PIPES.

SPECIFICATION forming part of Letters Patent No. 537,276, dated April 9, 1895.

Application filed August 31, 1892. I Serial No. 444,695. (No model.)

To aZZ whom, it may concern:

Be it known that I, CHARLES L. COFFIN, of Detroit, in the county of Wayne and State of Michigan, have invented a new and useful Improvement in Methods of and Apparatus for Butt-\Velding Pipes, of which the following is a specification.

My invention consists in an improved method of and apparatus for butt-welding pipes,hereinafter fully described and claimed.

Figure 1 is a vertical section on the line y-y, Fig. 2. Fig. 2 is a vertical central sec tion on line yy Fig. 1, omitting the frame and hammer actuating mechanism. Fig. 3 is a diagrammatic elevation of a modification adapted to welding hoops, and Fig. 4 illustrates a pipe blank with its edges turned up to afford more metal at the joint.

A represents the base of the machine carrying a series of small rollers E.

B represents a frame secured to and carried on base A.

0 represents a cylinder, which may be the whole length of a tube or pipe to be welded, or may be longer or shorter, and this cylinder is cut away along its upper surface, so that it is not a complete cylinder, as clearly shown in Fig. 1, though I shall call it a cylinder for the sake of brevity.

Cylinder O rests upon the rollers E, and is provided along its under side with a rack B, into which meshes a gear wheel P, by means of which the cylinder can be readily moved in either direction along the rollers E.

F and F represent ribs formed on opposite sides of the cylinder 0 which take into and slide in guide ways formed in frame B, as clearly shown in Fig. 1, by which said cylinder 0 is supported and guided as it moves along on rollers E.

G represents a set screw, having a hand wheel, tapped through frame B, and adapted to bear against rib F, whereby cylinder 0 can be slightly sprung and its diameter thus reduced, if the same should be necessary, to make it fit tightly the article to be welded.

NV, Figs. 1 and 2, represents a pipe or tube blank which is to be welded. The interior of cylinder 0 is intended to clamp the outer surface of said pipe or tube blank W with considerable snugness, and this may be aided by the set screw G if the fit is not tight enough.

S represents an arm or porter-bar pivoted at one end to a bracket T on bed A, and carrying at its other end a wheel 0, preferably set in spring bearings a, and an anvil N. The purpose of this bar is to enter the pipe or tube W and support the anvil close up against the under side of the seam, and also to carry the lower part of the heating furnace with which the same is heated. For these purposes, in order to compensate for slight inequalities in the pipe or tube, I prefer to use the spring bearing a, as shown in Fig. 2.

t represents a screw-shaft threaded through bracket '1 and with its end swiveled into arm S, whereby said arm can be raised or lowered.

H represents a frame carried on frame B, in which is supported a steam or pneumatic hammer K directly above anvil N, the cylinder of said hammer being indicated at J, and also carries the upper half L of the furnace, which furnace may be an electric furnace, as indicated by the electrodes 1' r, Fig. 1, or may be a gas furnace, or kerosene furnace, or any other suitable furnace. The upper half L of the furnace is carried upon a cross-head L which is made adjustable by the small screw shafts e, e, whereby said cross-head L and with it the upper half L of the furnace may be raised away from the work, or lowered to the work.

In Fig. 8, adapted for welding a ring W, the clamps b b may be rigid. The furnace L M in this case is represented as a gas furnace, the gas coming through the pipe 1). \Vith this apparatus, when the two parts which are to be welded are pressed together cold and then heated to a welding heat, the expansion of the metal presses the welding edges firmly together, thus making a weld, without the application of extraneous pressure.

In Figs. 1 and 2, the pipe or tube blank is rolled so that its edges are practically in contact, and if of very light metal, its edges may be turned up a little or upset to afford extra metal at the seam, as shown Fig. 4. It is placed cold in the cylinder 0 when said cylinder is in the machine, or may be placed in said cyl inder outside of the machine, and then with said cylinder is introduced into the machine in the position shown in Figs. 1 and 2. The edges of a blank to be welded together may be in'actual contact, or may bein such proximity to each other that the expansion of the heated portions of material will more than fill up the gap between the opposing edges. If the cylinder 0 does not fit the blank closely enough to bring its welding edges su tliciently near together, said cylinder is slightly pressed by the hand wheel G until the welding edges of the blank are brought to the proper position. The upperhalf Lof the furnace is now lowered down in close proximity to the pipe WV and heat is applied to the welding edges by any of the means hereinbefore set forth, and to such a length of the joint as the character of the work renders advisable. \Vhen the edges of the pipe are heated toa welding heat, the pipe tends to expand, but this tendency is restricted by the pressure of cylinder 0, and thus by its own expansion, the welding edges are pressed strongly together and a weld made. \Vhen this has been attained, and while the welding edges are still hot, the cylinder O and blank V are moved by means of gear P and rack R, (or any other suitable means) to bring the welded seam under hammer K and over anvil N, when the weld may be hammered if desired.

lVelding by this method can proceed at a rate which is governed only by the capacity of the furnace to heat the edges of the pipe to a welding heat, and in many cases may be so rapid as to permit of a steady movement of the cylinder 0 and blank IV through the machine.

In welding a ring, as shown in Fig. 3, the clamps l) b may be immovable, as the curved character of the Work will sufficiently compensate for any contraction strain after the weld has been formed by expansion.

The word cold is used in the specification and claims in a comparative sense only, and means any temperature which is so far below a welding heat that the metal will expand in being raised to a welding heat.

hat I claim as my invention, and desire to secure by Letters Patent, is

1. The method herein described of welding a pipe or tube, which consists in clampingthe tube rigidly on each side of the joint, and heating the portions between the clamps to a welding heat, whereby the expansion of the heated portions causes the joint to weld.

2. The herein described mode of welding tubes, consisting in bringing the edges to be welded in proximity while cold, holding the tubes in that position against expansion strain, and then heating the edges to be welded to a weldingheat.

3. The herein described mode of welding tubes, consisting in clamping the tubes with their edges in proximity when cold, raising the temperature of the parts to be welded to a welding heat, whereby the expansion of the tubes presses the welding edges together, and finally finishing the weld by rolling, ham mering or any other desired manner.

l. The herein described mode of welding metals, consisting in clamping the articles to be welded with the welding edges in proximity when cold, raising-the welding edges to a welding heat, resisting the tendency of the heated metal to expand, and permitting said metal to contract freely as it cools.

5. In an apparatus for welding a tube, the combination of a clamp for holding said tube rigidly against expansion except at the joint, and means for heating the edges of the tube to be welded, substantially as described, whereby the expansion of the tube causes its edges to be welded together.

6. In an apparatus for welding pipes or tubes, the combination with the cylinder O, for containing blank IV, means substantially such as described for slightly compressing said cylinder, and a furnace L M adapted to heat said blank alongthejoint, substantially as shown and described.

7. In an apparatus for welding pipes or tubes, the combination of a cylinder O, for containing blank WV, means substantially such as described for slightly compressing said cylinder, a furnace L M adapted to heat said blank along the joint, a reciprocating hammer adapted to hammer the welded seam, and an anvil carried within the blank, substantially as shown and described.

8. In an apparatus for welding pipes or cylinders, the pivoted arm S carrying the anvil N and supported by the roller 0 journaled in spring bearings, substantially as'and for the purposes set forth.

CHARLES L. COFFIN. IVitnesses:

GERTRUDE H. ANDERSON, Gno. H. LOTHROP. 

